Signs fall is finally upon us: the return of the pumpkin spice latte, back-to-school shopping, and the premiere of “The League,” television’s funniest (and only) fantasy football-related comedy. The sitcom moves from FX to the brand-new FXX channel (check which channel number it is in your area at getfxx.com) with its fifth-season premiere on Wednesday, Sept. 4 at 10:30/9:30c.